<!DOCTYPE html>
<html lang="en">

	<head>
		<meta charset="UTF-8">
		<title>最简单的轮播效果</title>
		<style>
			* {
				margin: 0;
				padding: 0
			}
			
			.box {
				width: 100%;
				height: 800px;
				border: 1px solid #ccc;
				margin: 0px auto;
				padding: 5px;
			}
			
			.inner {
				width: 100%;
				height: 800px;
				position: relative;
				overflow: hidden;
			}
			
			.inner img {
				width: 100%;
				height: 800px;
				vertical-align: top
			}
			
			ul {
				width: 1000%;
				position: absolute;
				list-style: none;
				left: 0;
				top: 0;
			}
			
			.inner li {
				float: left;
			}
			
			ol {
				position: absolute;
				height: 20px;
				right: 20px;
				bottom: 20px;
				text-align: center;
				padding: 5px;
			}
			
			ol li {
				display: inline-block;
				width: 20px;
				height: 20px;
				line-height: 20px;
				background-color: #fff;
				margin: 5px;
				cursor: pointer;
			}
			
			ol .current {
				background-color: red;
			}
			
			#arr {
				display: none;
			}
			
			#arr span {
				width: 40px;
				height: 40px;
				position: absolute;
				left: 5px;
				top: 50%;
				margin-top: -20px;
				background: #fff;
				cursor: pointer;
				line-height: 40px;
				text-align: center;
				font-weight: bold;
				font-family: '黑体';
				font-size: 30px;
				color: #000;
				opacity: 0.5;
				border: 1px solid #fff;
			}
			
			#arr #right {
				right: 5px;
				left: auto;
			}
		</style>
	</head>

	<body>
		<div class="box" id="box">
			<div class="inner">
				<!--轮播图-->
				<ul>
					
					<li>
						<a href="#"><img src="img/indexImg/shou.jpg" alt="" style="width: 1360px;height: 800px;"></a>
					</li>
					<li>
						<a href="#"><img src="img/indexImg/dian.jpg" alt="" style="width: 1360px;height: 800px;"></a>
					</li>
					<li>
						<a href="#"><img src="img/indexImg/shu.jpg"alt="" style="width: 1360px;height: 800px;"></a>
					</li>
					<li>
						<a href="#"><img src="img/indexImg/c.jpg" alt="" style="width:1360px;height: 800px;"></a>
					</li>
					
						
-->
				</ul>

				<ol class="bar">

				</ol>
				<!--左右焦点-->
				<div id="arr">
					<span id="left">
                        <
                    </span>
					<span id="right">
                        >
                    </span>
				</div>

			</div>
		</div>
		<script>
			
			function my$(id) {
				return document.getElementById(id);
			}

			//获取各元素，方便操作
			var box = my$("box");
			var inner = box.children[0];
			var ulObj = inner.children[0];
			var list = ulObj.children;
			var olObj = inner.children[1];
			var arr = my$("arr");
			var imgWidth = inner.offsetWidth;
			var right = my$("right");
			var pic = 0;
			//根据li个数，创建小按钮
			for(var i = 0; i < list.length; i++) {
				var liObj = document.createElement("li");

				olObj.appendChild(liObj);
				liObj.innerText = (i + 1);
				liObj.setAttribute("index", i);

				//为按钮注册mouseover事件
				liObj.onmouseover = function() {
					//先清除所有按钮的样式

					for(var j = 0; j < olObj.children.length; j++) {
						olObj.children[j].removeAttribute("class");
					}
					this.className = "current";
					pic = this.getAttribute("index");
					animate(ulObj, -pic * imgWidth);
				}

			}

			//设置ol中第一个li有背景颜色
			olObj.children[0].className = "current";
			//克隆一个ul中第一个li,加入到ul中的最后=====克隆
			ulObj.appendChild(ulObj.children[0].cloneNode(true));

			var timeId = setInterval(onmouseclickHandle, 9000);
			//左右焦点实现点击切换图片功能
			box.onmouseover = function() {
				arr.style.display = "block";
				clearInterval(timeId);
			};
			box.onmouseout = function() {
				arr.style.display = "none";
				timeId = setInterval(onmouseclickHandle, 9000);
			};

			right.onclick = onmouseclickHandle;

			function onmouseclickHandle() {
				//如果pic的值是5,恰巧是ul中li的个数-1的值,此时页面显示第六个图片,而用户会认为这是第一个图,
				//所以,如果用户再次点击按钮,用户应该看到第二个图片
				if(pic == list.length - 1) {
					//如何从第6个图,跳转到第一个图
					pic = 0; //先设置pic=0
					ulObj.style.left = 0 + "px"; //把ul的位置还原成开始的默认位置
				}
				pic++; //立刻设置pic加1,那么此时用户就会看到第二个图片了
				animate(ulObj, -pic * imgWidth); //pic从0的值加1之后,pic的值是1,然后ul移动出去一个图片
				//如果pic==5说明,此时显示第6个图(内容是第一张图片),第一个小按钮有颜色,
				if(pic == list.length - 1) {
					//第五个按钮颜色干掉
					olObj.children[olObj.children.length - 1].className = "";
					//第一个按钮颜色设置上
					olObj.children[0].className = "current";
				} else {
					//干掉所有的小按钮的背景颜色
					for(var i = 0; i < olObj.children.length; i++) {
						olObj.children[i].removeAttribute("class");
					}
					olObj.children[pic].className = "current";
				}
			}
			left.onclick = function() {
				if(pic == 0) {
					pic = list.length - 1;
					ulObj.style.left = -pic * imgWidth + "px";
				}
				pic--;
				animate(ulObj, -pic * imgWidth);
				for(var i = 0; i < olObj.children.length; i++) {
					olObj.children[i].removeAttribute("class");
				}
				//当前的pic索引对应的按钮设置颜色
				olObj.children[pic].className = "current";
			};

			//设置任意的一个元素,移动到指定的目标位置
			function animate(element, target) {
				clearInterval(element.timeId);
				//定时器的id值存储到对象的一个属性中
				element.timeId = setInterval(function() {
					//获取元素的当前的位置,数字类型
					var current = element.offsetLeft;
					//每次移动的距离
					var step = 10;
					step = current < target ? step : -step;
					//当前移动到位置
					current += step;
					if(Math.abs(current - target) > Math.abs(step)) {
						element.style.left = current + "px";

					} else {
						//清理定时器
						clearInterval(element.timeId);
						//直接到达目标
						element.style.left = target + "px";
					}
				}, 10);
			}
		</script>
	</body>

</html>